Hey, I drive a 1997 GMC Jimmy, and the bottom of the motor took a crap. I have an extra 1994-95 (manufactured at the end of 94 but 95 model year) both have 4.3l of course, but my newer one has the newer, more efficient engine, and the older one has the older, and supposedly more powerful engine. I've looked at EPA MPG and the HP/TQ differences, and the newer motor had plenty of HP/TQ, and great MPG. I've read that the older ones had a little less MPG, but more horsepower and torque. I'm trying to decide whether to convert to the old style and enjoy the power, or if the difference is even noticeable. The Jimmy is my daily driver, so I would prefer the better gas mileage, however if the older motor will have a noticeably higher HP/TQ for only a little sacrifice on fuel mileage, then I'm fine with that. Just looking for some input here. Thanks in advance!

 

DO NOT even think about it. The older CPI engine had many issues with the fuel system that you don't even want to consider reverting back to it. Get a hold of another 96+ SCFI motor and happily motor on.

 

Thanks for the quick response Swart! I was doing the teardown on the 95 Blazer earlier today, so I guess I'll just take the parts I need, and sell the rest! If anyone on here needs any parts off of it, the motor, transmission, and rear-end are spoken for, but if anyone needs anything off of the 95 one, then message me on here and we'll make a deal. I'm located in central Illinois, so if anyone is close, just let me know and we can get things sorted on pickup/delivery.
Again, thank-you Swart for the helpful information! There doesn't seem to be alot of advice on this sort of thing on the web. Just numbers!